Light is commonly held to be essential to life, be the life human, animal, or plant-based. However, natural light (i.e., the portion of the electromagnetic radiation given off by the sun) faces any number of impediments, including the atmosphere, the setting of the sun, landforms, man-made structures, etc. Plants are especially sensitive to lighting conditions. As such, grow lights, or plant lights, have been developed to provide an artificial light source similar to the light spectrum of the sun to stimulate plant growth where there is no naturally occurring light, or where supplemental light is required.
As such, artificial lighting has been used to provide illumination where natural light cannot, as well as in conditions in which the artificial lighting is complementary to natural lighting. Artificial light is composed of visible light, as well as ultraviolet and infrared radiations. Various forms of artificial lighting include incandescent light bulbs, fluorescent tubes, light-emitting diodes, etc., to produce visible light.
Sensitivity to light in humans, medically referred to as photophobia, is a symptom of abnormal intolerance to visual perception of light. Such exposure to natural light and/or artificial light can be felt as an experience of discomfort or pain to the eyes due to light exposure. Additionally, sensitivity to light can be a symptom of underlying diseases that don't directly affect the eyes (e.g., viral illness, headaches, etc.). As a result of the proliferated use of artificial lighting, concern exists that the emission levels of some artificial light sources could be harmful to the skin and/or the eyes. Both natural light and artificial light can disrupt the human body clock and the hormonal system, which can lead to health problems.